Bit-stock



(Nomadel.)

W. S. DAVIS.

BIT STOCK.

I Patented Jan. 6, 1891.

UNITED STATES ArsNT FFCE.v

BIT-STOCK.

SPECIFICATION forming part of Letters Patent No. 443,989, dated January 6, 189i.

Application led February 15, 1889. Serial No. 300,062. (No model.)

.To all whom t may concern.-

Be it known that I, WINFIELD S. Davis, of Florence, in the county of Hampshire and Commonwealth of Massachusetts, have invented a new and useful Improvement in Bit- Stocks, of which the following is a specification, reference being had to the accompanying drawings, forming part thereof.

My invention relates to that class of bitstocks in which means are provided for increasing the number of revolutions made by the bit over the number made by the crankshaft; and it has for its object to provide neat and compact means for this purpose which are protected from dirt and from danger of contact with the person or clothing of the user of the device.

To this end my invention consists in the bit-stock constructed and operating as hereinafter fully described, and particularlypointed out in the claims.

Referring to the drawings, in which like letters and figures designate like parts in the several figures, Figure l is a view in' perspective of the bit-stock devised by me. Fig. 2 is a cross-section of the crank, taken upon line a; :c of Fig. 3 and showing the gear-casing in side elevation. Fig. 3 is avertical section gif the gear-casing, taken upon line y y of The letter A designates the crank-shaft, which terminates at its rear end in the usual swiveled head a and has its front end seated within a hub b in gear-casing B, within which it is retained by a nut a. The gear-casing B, which forms one of the arms of crank A, consists of a ilattened hollow receptacle having at its inner end the enlarged portion b', of which the internal hub b forms the center, and having at its outer end the external hub b2, which is threaded internally to receive nut b3. Upon its rear side the casing is provided with a removable cap-plate b4, conforming substantially in shape to said casing and extending from the inner end nearly to the outer end of the latter, as shown. The capplate b4 is provided with a circular opening concentric with hub b, the inner edge of which opening is preferably beveled, as shown in Fig. 3. The cap-plate is held in place by screws or in any suitable manner7 and when removed affords access to the interior of the casing.

Located within the casing is a train of gears, preferably four in number and designated by the numerals l 2 3 4. Gear 1 is rigidly secured to or is formed integral with a sleeve O, mounted loosely upon crankAin the usual manner, said sleeve having its outer surface.

milled or otherwise roughened to enable it to 6o be grasped firmly to prevent rotation thereof about its axis. The front end of sleeve C has its bearing upon hub b of the casing, as shown in Fig. 3, and the central portion of gear 1 is preferably made concave-convex in crosssection, as shown, to lessen its weight and to enable its rear side, which projects through the opening in the cap-plate, to more effectually guard the hand of the user from contact with the side of casing B. Gears 2 and 3 7o have their axes mounted in bearings in the front wall of the casing and the cap-plate, respectively. Gear 4 is rigidly secured upon the hub d of a tool-carrying shaft D, which has its bearings in nut b3 and the rear Wall of 75 the casing, respectively. Said shaft D will be provided at its front end with any of the usual means for receiving and holding the tools.

In Fig. l I have shown a screw-driver as 8o the tool employed, and in Fig. 3 have shown a common form of tool-chuck E, having its tapering shank e seated within a tapering socket in shaft D; but it will be understood that these are shown as examples merely of the various tools which are ordinarily usedl in a bit-stock and the various devices for holding the same. By removing nut b3 the end of shaft D with gear 4: secured thereon can be inserted within the casing, whereupon said 9o nut is replaced and securely retains said shaft and gear in position. It will be observed that by means of the train of gears arranged as described a revolving movement will be imparted to shaft D and the tool carried thereby by firmly grasping sleeve C to prevent revolution thereof about its own axis and by turning crank A in the usual manner, the tool being caused thereby to revolve in the direction of said crank; movement. The speed at roc which the tool will be revolved relatively to the movement of the crank will obviously depend upon the size ofgears 2, 3and 4 relatively to that of gear 1. I prefer to provide. the gears 2, 3, and 4 with one-fourth the number of teeth carried by gear 1, and thus cause the tool to make five revolutions to each revolution of the crank A; but said relative proportions can be varied at will. The friction created by the train of gears is very slight, and therefore little or no eXtra force is required to operate the bit-stock thus constructed, While the greater diameter of gear l enables sleeve C to be held from revolution about its own axis very easily.

The removable cap-plate enables the parts to be assembled easily, and when said plate is secured in place the casing entirely incloses the train of gears, thereby protecting them from dust and dirt of all kinds and at the same time effectually protecting the hand and clothing of the user from contact with said gears.

Lne accelerated motion of the tool-carrying shaft effects a great saving in time and labor in all of the uses to which a bit-stock is put and is particularly advantageous in starting drills into metal and Wood-screws into wood.

' described.

2. In a bit-stock, the combination, with crank A, of casing lsecured to one end thereof, said casing having annular hub b2 and removable cap-plate btool-carrying shaft D, having its bearing in said hub b2, and a train of gears located within said casing and connecting a sleeve on said crank With said toolcarrying shaft, arranged and operating substantially as set forth.

W'INFIELD S. DAVIS.

Witnesses:

W. H. CHAPMAN, J. E. CHAPMAN. 

